HI,

Looks nice, but I think you need a SSL certificate?

You don't need one with Paypal

Thanks for mentioning Stripe.com, it is exactly what I needed.

I saw them when they launched and it looks pretty solid (like Square for websites).

My only issue so far?
"Do I need to be in the United States to use Stripe?
Yes. At the moment, you must be based in the US to receive payments; this involves both having a U.S. address, and having a significant shareholder of the company with a valid SSN."

But there's hope:
"Rest assured, we're working hard on expanding to other countries. Many of us at Stripe are from outside the United States, and we understand just how broken the non-US payments landscape is. Sign up here to be notified when Stripe is available in your country"

Stripe has a couple cheap SSLs they recommend on their site here:
http://stripe.com/help/ssl

... anyone working with this yet on a C5 site?

What about this free SSL:
http://www.freessl.com/

I implemented stripe in a static html page and it was fairly easy. I received amazing help in their live chat which was really great!

For reference, here's the payment method in the marketplace:
http://www.concrete5.org/marketplace/addons/ecommerce-stripe-paymen...

Stripe is also available in Canada and very soon the UK.
I developped a membership add-on for a customer using Stripe she's very happy with their level of service (and the add-on :)

is the add-on in the marketplace?

No. It will eventually but it needs to be modified and added to